{
    "description": "Banner Ad Without Sizes Defined",
    "mockBidRequest": {
        "id": "some-request-id",
        "site": {
            "page": "test.somepage.com"
        },
        "imp": [{
            "id": "some-imp-id",
            "banner": {},
            "ext": {
                "prebid": {
                    "bidder": {
                        "appnexus": {
                            "placementId": 12883451
                        }
                    }
                }
            }
        }]
    },
    "expectedErrorMessage": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.",
    "expectedReturnCode": 400
}